The present disclosure relates to a fixture for testing operation of an electrically driven automotive component. More particularly, the present invention relates to a test fixture for testing operation of automotive wiper systems.
Many different configurations of wiper systems exist for vehicles. It is desirable to test operational performance of these wiper systems under controlled conditions. In particular, measuring forces at the vehicle to wiper linkage connection locations under realistic operating loads can be correlated to in-vehicle noise performance of the wiper systems.
The test fixture of the present disclosure measures the vehicle to wiper system connection location forces under an approximation of an infinite-mass boundary condition; this measurement method is known as a “blocked force measurement”. The test fixture of the present disclosure illustratively measures forces at the connection points between the wiper system and the vehicle in three translational directions while approximating an infinite-mass boundary condition. The test fixture illustratively applies a user-adjustable smooth resistive torque to the wiper arm connection points of the wiper system to provide an appropriate operating load. The test fixture of the present disclosure has flexible mounting configurations to accommodate the many different wiper system configurations that exist.
Resonant frequencies of test fixture support structures can introduce errors in test fixture measurements. The test fixture of the present disclosure is designed to avoid the effects of these test fixture resonances in the frequency range of interest for the test procedures.
Within an illustrated embodiment of the present disclosure, a test fixture is provided for a wiper system including a linkage and a motor coupled to the linkage. The linkage includes a plurality of connection points and first and second wiper arm connectors. Wiper systems without a linkage or with a differing number of connection points and/or wiper arm connectors can also be tested by the fixture of the present disclosure. The test fixture includes first and second spaced apart support walls, each support wall having an inner surface and a top surface, a base located between the inner surfaces of the first and second support walls, and first and second tracks coupled to the top surfaces of the first and second support walls, respectively. The test fixture also includes first and second cross beams moveably coupled to the first and second tracks, and first and second brake assemblies coupled to the first and second cross beams, respectively. The first and second brake assemblies each include a brake support structure coupled to a respective one of the first and second cross beams so that each brake support structure is moveable along a longitudinal axis of the cross beam and is also rotatable relative to the cross beam. The first and second brake assemblies also include a brake coupled to the brake support structure and a connector coupled to a brake shaft of the brake. The connector is configured to be coupled to one of the wiper arm connectors of the linkage so that the brake applies a resistive torque to the wiper arm connector. The test fixture further includes a torque sensor mounted to each brake shaft of the first and second brake assemblies, the torque sensor measuring the resistive force applied by the brake to the wiper arm connector. The test fixture still further includes a plurality of mounting blocks configured to be coupled to the base at a plurality of selected locations. Each mounting block includes a coupler configured to be coupled to one of the connection points of the linkage of the wiper system. The test fixture also includes a plurality of force sensors. A force sensor is coupled between each coupler and the connection point of the wiper system. The force sensors measure forces at the connection points of the wiper system during movement of the wiper system by the motor.
Additional features and advantages of the present system will become apparent to those skilled in the art upon consideration of the following detailed description of illustrative embodiments exemplifying the best mode of carrying out the present system as presently perceived.